Elastomeric connectors have been developed to interconnect the closely spaced circuits of substrates and printed circuit boards and the like through the use of contacts that are fabricated by etching away thin copper foil from an insulating film carrying support, which in turn is wrapped around an elastomeric body. Upon compression, the elastomeric body drives the contacts into engagement with contact pads or traces on substrates or printed circuit boards. One such device is shown in U.S. Pat. No. 3,985,413 granted Oct. 12, 1976. Another is shown in U.S. Pat. No. 4,057,311 granted Nov. 8, 1977. These connector concepts allow interconnection of circuit paths on spacings far less than 0.050 inches, spacings on the order of 0.025 inches or less and provide a low resistance, stable interface of large numbers of interconnections with minimum path lengths to reduce the impedance presented by the connectors.
As transmission speeds increase, rise time of signal pulses decreases and traditional single conductor power and signal circuits no longer work adequately; the lack of impedance control causing circuit ringing, signal delays and losses, reflections, as well as creating cross-talk between signal lines. With certain signal transmission problems in circuit boards, such as printed circuit boards, resort has been made to strip line and micro strip line techniques. There, ground planes are positioned relative to signal lines in terms of spacing, and dielectric constant parameters to control the impedance of circuit transmission to and from a functioning component, such as integrated circuits and input and output transmission lines.
Alternatively, resort has been made to compensating connector segments to provide impedance matching, and a variety of other techniques, generally large in size and complicated in structure and assembly.
Accordingly, it is an object of the present invention to provide an elastomeric connector having a controlled impedance to match the impedances utilized by the circuits, substrates, or printed circuit boards and the like, interconnected by such connector. It is a further object to provide a simple and reliable elastomeric connector having controlled impedance characteristics and capable of interconnecting large numbers of closely spaced circuit paths. It is still a further object to provide an improved controlled impedance connector that is small in size and presents physically and electrically a reduced path length of interconnection.